Soil Classification E Footing Ties

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Need some advice. I have a single story all steel structure (OCBF S-R system) on Soil Classification E. The foundation design used elsewhere (in better soils!) employs simple shallow spread footings with a mono-pour slab above (thickened edges around the perimeter.

Now, with Soil Classification E, I need to tie all the footings together. I assume this code requirement means that both orthogonal directions need to be accommodated.

My real concern here is that the foot print of this building is quite odd. Columns are not on a nice grid. In fact, few columns really line up nicely (thanks Mr. Architect!) in either direction.

Any insights here that anyone can share?

On thought I had was to use thickened "beam" sections in the mono pour slab. I could provide dowels at the spread footings to create a positive connection to the slab-beams. Similar to a stiffened slab, but the beams won't all line up nicely due to the odd column layout. Rather, I would consider thickening the slab (plus added reinforcing) to use it as a diaphragm rather than place intersecting slab-beams into lateral bending as a result of misaligned grid. Thoughts?

Note that the building is about 100 ft x 100 ft.

 

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Had another idea... the maximum column load is only about 60 kips (factored). The resultant lateral design load for any column is under 6 kips as a result. Considering this load is quite small, the alternate idea would be to design similar to a pre-engineered metal building foundation in the sense of using weldable rebar or hairpins at the columns to lock them out the slab. No grade beams other than a thickened edge at the perimeter. The slab itself would simply be made thicker and more conventionally reinforced (i.e. 6" slab instead of 4" with #3 @ 16" o.c. minimum possibly).

Sound reasonable?